Para hallar los extremos hay que resolver la ecuación
$$\frac{d}{d x} f{\left(x \right)} = 0$$
(la derivada es igual a cero),
y las raíces de esta ecuación serán los extremos de esta función:
$$\frac{d}{d x} f{\left(x \right)} = $$
primera derivada$$\frac{16 \sin^{7}{\left(2 x + 1 \right)} \cos{\left(2 x + 1 \right)}}{x} - \frac{\sin^{8}{\left(2 x + 1 \right)}}{x^{2}} = 0$$
Resolvermos esta ecuaciónRaíces de esta ecuación
$$x_{1} = -39.7690415814106$$
$$x_{2} = 44.2669893704748$$
$$x_{3} = -83.7521092873697$$
$$x_{4} = 92.180126112679$$
$$x_{5} = 74.1124038660448$$
$$x_{6} = -16.1985985143369$$
$$x_{7} = 49.7757257662834$$
$$x_{8} = 40.336793162601$$
$$x_{9} = 76.4601213216483$$
$$x_{10} = 54.4686723668636$$
$$x_{11} = -31.9197914147873$$
$$x_{12} = 27.7842773228085$$
$$x_{13} = 70.1886099012152$$
$$x_{14} = 88.249638354871$$
$$x_{15} = 15.9914072668152$$
$$x_{16} = -71.9707986653973$$
$$x_{17} = -99.4711782805252$$
$$x_{18} = -61.7605753228223$$
$$x_{19} = -79.8248230209888$$
$$x_{20} = -91.6107854724706$$
$$x_{21} = -93.9620488632621$$
$$x_{22} = -9.92833487169884$$
$$x_{23} = 59.9751375325493$$
$$x_{24} = 85.8988650413369$$
$$x_{25} = -68.0421030359746$$
$$x_{26} = -97.8925874929779$$
$$x_{27} = 78.0378906643915$$
$$x_{28} = -38.1900904311503$$
$$x_{29} = 41.9157442133507$$
$$x_{30} = 4.21402137509175$$
$$x_{31} = 26.2055546761109$$
$$x_{32} = -82.1730790172552$$
$$x_{33} = 56.0463169921838$$
$$x_{34} = 32.4772279170461$$
$$x_{35} = -47.6292673192466$$
$$x_{36} = 30.1294911842192$$
$$x_{37} = -60.1815810258627$$
$$x_{38} = -2.06736574465965$$
$$x_{39} = -17.777508108349$$
$$x_{40} = -24.0589560466668$$
$$x_{41} = 37.9836872856169$$
$$x_{42} = 66.2583722504124$$
$$x_{43} = -13.8495123959454$$
$$x_{44} = -5.99257254408229$$
$$x_{45} = 98.4515767826663$$
$$x_{46} = 100.029466114261$$
$$x_{47} = -63.3418850336411$$
$$x_{48} = -53.9110872390394$$
$$x_{49} = -75.9021061862936$$
$$x_{50} = -25.6377544056686$$
$$x_{51} = 93.7585737823487$$
$$x_{52} = -90.0336781637965$$
$$x_{53} = 8.13553870136171$$
$$x_{54} = 84.3198428328977$$
$$x_{55} = -55.4884078858686$$
$$x_{56} = 12.0631874938417$$
$$x_{57} = -96.3062821196124$$
$$x_{58} = -41.3517449056536$$
$$x_{59} = 79.6227585650116$$
$$x_{60} = -42.9209407951649$$
$$x_{61} = -49.9794590374976$$
$$x_{62} = -27.9878191636024$$
$$x_{63} = 52.121077382413$$
$$x_{64} = 62.3283170984472$$
$$x_{65} = -57.833525584199$$
$$x_{66} = 81.9664259031444$$
$$x_{67} = 63.9073065448004$$
$$x_{68} = 22.2751438331967$$
$$x_{69} = 96.1036489281767$$
$$x_{70} = 90.5939688866853$$
$$x_{71} = 48.1970842850461$$
$$x_{72} = -74.3150164941039$$
$$x_{73} = -77.479799595138$$
$$x_{74} = -35.8420454727256$$
$$x_{75} = -64.9083490646998$$
$$x_{76} = -46.0505290330457$$
$$x_{77} = -33.4970017468524$$
$$x_{78} = -91.6122792204312$$
$$x_{79} = -85.3311398318543$$
$$x_{80} = -69.620775460956$$
$$x_{81} = -14.6285220385696$$
$$x_{82} = 34.0547473579879$$
$$x_{83} = 18.3452698401653$$
$$x_{84} = 19.9241779101437$$
$$x_{85} = -3.64621911498531$$
$$x_{86} = 71.7671571612764$$
$$x_{87} = 68.6027670409628$$
Signos de extremos en los puntos:
(-39.76904158141065, -2.04736992557217e-24)
(44.26698937047478, 0.0225900166367254)
(-83.7521092873697, -2.21105461291369e-32)
(92.180126112679, 2.6433147377044e-20)
(74.11240386604479, 0.0134929796245852)
(-16.19859851433693, -9.34394416832983e-16)
(49.77572576628337, 6.23019252809181e-16)
(40.33679316260098, 3.47618151980688e-19)
(76.46012132164826, 1.31592365898015e-16)
(54.4686723668636, 2.40906721454624e-16)
(-31.919791414787305, -3.99238519887195e-19)
(27.784277322808464, 8.80045812691833e-16)
(70.18860990121516, 1.2832287376428e-20)
(88.24963835487101, 0.0113314684609724)
(15.991407266815209, 0.0625297626958592)
(-71.97079866539733, -0.0138944822347557)
(-99.47117828052522, -5.55217872132451e-16)
(-61.76057532282229, -1.19601560764386e-26)
(-79.82482302098884, -0.0125274007511097)
(-91.6107854724706, -5.58711720043359e-19)
(-93.9620488632621, -0.0106425758307417)
(-9.928334871698837, -6.6056896155952e-19)
(59.975137532549304, 0.0166735033428155)
(85.89886504133695, 1.29493111972596e-18)
(-68.04210303597458, -1.64878580212547e-21)
(-97.89258749297791, -2.98651298299217e-20)
(78.03789066439153, 6.2028378655372e-22)
(-38.1900904311503, -2.93965846685813e-16)
(41.915744213350685, 6.41984546558787e-19)
(4.2140213750917495, 3.06293995046942e-21)
(26.20555467611087, 2.67726954519918e-21)
(-82.17307901725518, -7.2193769344955e-17)
(56.046316992183776, 4.25956058279443e-21)
(32.477227917046115, 5.20465630337809e-16)
(-47.629267319246594, -3.75796201611612e-18)
(30.129491184219223, 0.033189501338378)
(-60.1815810258627, -1.36935625387709e-16)
(-2.0673657446596483, -2.37540662491414e-18)
(-17.777508108348954, -8.66511864804943e-23)
(-24.058956046666815, -6.77612742585817e-20)
(37.983687285616874, 0.0263268061002243)
(66.25837225041244, 0.0150923786226206)
(-13.84951239594544, -0.0721988265227307)
(-5.992572544082289, -0.166800653073985)
(98.45157678266634, 7.71830195807645e-17)
(100.02946611426103, 6.51714983801152e-23)
(-63.3418850336411, -4.14383873405849e-16)
(-53.91108723903943, -3.18803324057877e-19)
(-75.90210618629362, -1.74117756545954e-19)
(-25.637754405668616, -3.98296091022217e-18)
(93.75857378234872, 5.02891877571803e-16)
(-90.03367816379654, -2.10280399824959e-22)
(8.135538701361709, 0.122888477080844)
(84.31984283289775, 3.00939730588116e-20)
(-55.48840788586863, -7.00381066535669e-16)
(12.063187493841742, 2.23655238148007e-19)
(-96.30628211961239, -1.38588955793292e-15)
(-41.35174490565356, -1.36566785866734e-15)
(79.62275856501158, 1.52159198850622e-15)
(-42.920940795164874, -3.75949803953792e-16)
(-49.979459037497605, -0.0200080946081427)
(-27.98781916360241, -0.0357291165562022)
(52.121077382412984, 0.0191859857581803)
(62.328317098447194, 1.00368507968916e-19)
(-57.83352558419898, -0.0172909280277426)
(81.96642590314441, 0.0122000887963)
(63.90730654480042, 8.8633560505496e-19)
(22.275143833196726, 0.0448916746688043)
(96.10364892817674, 0.010405414564261)
(90.59396888668533, 1.40221639031e-15)
(48.19708428504606, 5.81062717119916e-21)
(-74.3150164941039, -1.9374169490801e-15)
(-77.47979959513805, -6.02001747531436e-16)
(-35.84204547272561, -0.02789985404233)
(-64.9083490646998, -4.39197113354359e-18)
(-46.0505290330457, -1.03976663154432e-20)
(-33.49700174685237, -9.51824931894044e-16)
(-91.61227922043123, -5.30189780391124e-18)
(-85.3311398318543, -5.77031401800756e-17)
(-69.62077546095601, -4.31472695975375e-18)
(-14.628522038569551, -5.45691565261464e-16)
(34.054747357987914, 2.61926303534964e-20)
(18.345269840165344, 1.58911968440939e-18)
(19.92417791014365, 5.89492466247743e-19)
(-3.6462191149853123, -1.47346276579505e-17)
(71.76715716127636, 5.37287813086988e-16)
(68.6027670409628, 1.91727709501533e-15)
Intervalos de crecimiento y decrecimiento de la función:Hallemos los intervalos donde la función crece y decrece y también los puntos mínimos y máximos de la función, para lo cual miramos cómo se comporta la función en los extremos con desviación mínima del extremo:
Puntos mínimos de la función:
$$x_{1} = -71.9707986653973$$
$$x_{2} = -79.8248230209888$$
$$x_{3} = -93.9620488632621$$
$$x_{4} = -13.8495123959454$$
$$x_{5} = -5.99257254408229$$
$$x_{6} = -49.9794590374976$$
$$x_{7} = -27.9878191636024$$
$$x_{8} = -57.833525584199$$
$$x_{9} = -35.8420454727256$$
Puntos máximos de la función:
$$x_{9} = 44.2669893704748$$
$$x_{9} = 74.1124038660448$$
$$x_{9} = 88.249638354871$$
$$x_{9} = 15.9914072668152$$
$$x_{9} = 59.9751375325493$$
$$x_{9} = 30.1294911842192$$
$$x_{9} = 37.9836872856169$$
$$x_{9} = 66.2583722504124$$
$$x_{9} = 8.13553870136171$$
$$x_{9} = 52.121077382413$$
$$x_{9} = 81.9664259031444$$
$$x_{9} = 22.2751438331967$$
$$x_{9} = 96.1036489281767$$
Decrece en los intervalos
$$\left[-5.99257254408229, 8.13553870136171\right]$$
Crece en los intervalos
$$\left(-\infty, -93.9620488632621\right]$$